Slack adjuster



March 27, 1928. 1,663,623

J. W. CLARK SLACK ADJUSTER Filed Dec. 30. 1926 2 Sheets-Sheet 1 J lari March 27, 1928.

- J. w. CLARK SLACK ADJUSTER Filed Dec. 50. 1925 Patented Mar. 27, 1928.

UNITED STATES JAMES W. CLARK, OF MONMOU'IH, ILLINOIS.

SLACK Amusma.

Application filed December 30, 1928. Serial No. 158,011.

This invention relates to slack adjusters for use with air brake equipment for railway cars, locomotives, tenders, urban and interurban cars and the like, and it is primarily an object of the invention to provide a slack adjuster operable through the instrumentality of a capstan.

In air brake equipment it is highly important to maintain uniform the piston travel as on such uniform operation or movement depends the power and efficiency of the air brake equipment.

It is another object of my invention to provide means operating under influence of the rod of the brake cylinder to take up automatically any slack that may occur as a result of wear upon the brake shoes or from any other cause which would effect the desired uniform travel of the piston.

The invention consists in the details of construction and in the combination and arrangement of the several parts of my improved slack adjuster whereby certain important advantages are attained and the device rendered simpler, less expensive and otherwise more convenient and advantageous for use, as will be hereinafter more fully set forth.

The novel features of my invention will hereinafter be definitely claimed.

In order that my invention may be the better understood, I will now proceed to describe the same with reference to the accompanying drawings, wherein Figure 1 is a diagrammatic view illustrat-- ing a slack adjuster constructed in accordance with an embodiment of my invention;

Figure 2 is a diagrammatic view illustrating an adjuster constructed in accordv ance with a further embodiment of my invention;

Figure 3 is a fragmentary view partly in section and partly in elevation illustrating the mounting of the capstan and certain of the parts associated therewith;

Figure/1 is an enlarged fragmentary view partly in section and partly in elevation fur-.

ther illustrating in detail the structure particularly illustrated in Figure 3;

Figure 5 is a fragmentary sectional view taken substantially on the line 55 of Figure 4;

Figure 6 is a taken substantially on the line 66 of Figure 4;

Figure 7 is a diagrammatic view illustratfragmentary sectional view ing a still further embodiment of my invention; Figure 8 is a diagrammatic view illustrating an additional form of invention.

My improved slack adjuster may be employed in connection with the regular brake equipment without any material change in the arrangement of the brake rigging.

As particularly illustrated in Figure 1, C denotes a brake cylinder in which operates a well known type of piston carrying the push rod 1. The rod 1 is voperatively engaged through the medium of a pin 2 with the live cylinder lever 3 which constitutes parts of all air brake equipment.

The pin 2 also provides an operative connection between the rod 1 and an end portion of the operating lever 4 comprised in my improved slack adjuster. The rectilin ear movement of the push rod 1 imparts swinging movement to the lever 4 as well as the live cylinder lever 3 and for which reason said lever 4 is provided with a slot 5 through which the pin 2 is disposed in order to provide for such swinging movement. The lever 4 has pivotal engagement with the lower portion of a pin 6. This pin 6 is supported by a car sill 7 and a bracket 8 secured to such sill and herein disclosed asdepending therefrom.

Rotatably mounted upon the pin 6 is a capstan A provided with the upper and lower flanges 9 and 10. The peripheral poreach of the teeth 12 being provided with a short ratchet tooth 14. The lever 4 has pivotally connected therewith, as at 15, a dog or pawl 16 which is constantly urged into contact with a tooth 11 through the medium of the spring 17 carried by the lever 4. Pivotally engaged, as at 18, with the sill 7 is a second pawl 1.9 constantly urged into contact with the flange 9 through the medlum of the spring 20 also carried by the sill 7 Winding on the capstan A between the flanges 9 and 10 is a cable 21 the extremities of which being operatively en aged, as at 22, with the free extremities of t e levers 23.

III.

As is particularly illustrated in the accompanying drawings, it is to be noted that the central portion of the cable 21 is suitably attached or anchored, as at 2 1, to the capstan A so that upon rotation of such capstan under the influence of the pawl 16 pull will be imposed upon the outer or free end portions of both of the levers 23 or, in other words, the free end portions of the levers 23 will be moved inwardly or one toward the other.

The opposite end portions of the levers 23 are pivotally connected, as at 25, with the extremities of the tie rod 26. The central portion of each of the levers 23 has pivotally connected therewith, as at 27, a rod 28. This rod 28 in turn is operatively engaged with an end portion of a dead lever 29 comprised in the foundation for regular brake rigging. Associated with each of the rods 28 1s a guide bracket 30 and interposed between each of said brackets 30 and the adjacent end of the dead lever 29 is a coil spring 31 encircling the rod 28. This spring 31 is of a tension to keep the dead lever 29 in place and permitting the brakes tobe released.

As the rod 1 moves outwardly swinging movement is imparted to the lever 4 and in the event the outward movement of the rod, or the piston travel, is for a distance greater than the uniform travel desired, the pawl 20 will engage a small tooth 14 and holds the capstan A against retrograde rotation. lVhen the brakes are released and the operating lever 4 with its pawl 16 moves backwardly the pawl 16 will engage the tooth 11 immediately succeeding the tooth with which it previously co-operated and when the brakes are again applied and the rod 1 moved outwardly, the capstan A will be rotated'a distance sufficient to bring the pawl 20 into coaction with the long tooth 12 immediately adjacent the short tooth 14 with which it was previously engaged. By this action the slack is taken out of the brake gear rigging and it will be noted that the desired uniform travel of the brake piston or rod 1 is maintained.

Under normal conditions or when the movement of the brake piston is uniform, it will be understood that the swinging movement of the operating lever 4 will have no effect upon the capstan A.

The embodiment of my invention as illustrated in Figure 2 is of a character especially intended for use in connection with a certain type of passenger car equipment and in this form of my invention the cable 21' leads from the capstan A to a lever 32 pivotally supported, as at 33, substantially midway its ends. This lever 32 is operatively engaged, as at 34, with a block 35 which is also operatively engaged with a dead cylinder lever 36. This block 36 has movement between the guides 37 and is constantly urged inwardly toward the cylinder C through the medium of the spring 38 of requisite tension.

Inthe embodiment of my invention as illustrated in Figure 7, the extremities of the cable 21 are secured to the extremities of the levers 23, said levers at desired points intermediate their ends being pivotally connected, as at 25, with the tie rod 26". The opposite extremities of the levers 23 are pivotally connected, as at 27, with the reversely directed rods 28 each of which in turn is operatively engaged with a dead lever, such as a lever 29 illustrated in Figure 1. This embodiment is particularly desirable when desired to transmit power to the side of the rolling stock opposite to or remote from the capstan as under some conditions the capstan and dead lever cannot be arranged at the same side.

In Figure 8 I disclose an embodiment of my invention wherein indirect movement is provided to take up the slack or to transmit the power;to the opposite side of the rolling stock at one end only. In this embodiment, the rod 28 is operatively connected with an extremity of a first-class lever 39. This lever 39 at a desired point intermediate its ends is suitably fulcrumed, as at 40. The opposite end portion of the lever is connected by the rod 41 with a dead lever 29'. Coacting with the dead lever 29 is a spring 31' forholding such lever in place, thus permitting the brakes to release.

It is to be understood that the capstan A is to be set with respect to the center of travel of the pin 2 in accordance with the required uniform travel of the brake piston. Railroad cars generally are supposed to have an eight inch piston travel and in which case the capstan A should be set approximately fourteen inches from the center of travel of the pin 2, while such pistons for tenders are supposed to have a running travel of six inches. In this latter equipment the capstan, therefore, should be set approximately ten and one-half inches from the center of travel of the pin 2. In locomotives the piston generally has a runnin travel of four inches and in connection Wit such equipment the capstan should be set approximately seven inches from the center of travel of the pin.

From the foregoing description it is thought to be obvious that a slack adjuster constructed in accordance with my invention is particularly well adapted for use by reason of the convenience and facility with which it may be assembled and operated, and it will also be obvious that my invention is susceptible of some change and modification without departing from the principles and spirit thereof and for this reason I do not wish to be understood as limiting myself to the precise arrangement and formation of the several parts herein shown in carrying outmy invention in practice exceptas hereinafter claimed.

I claim l. The combination with the push rod. a dead lover of an air brake equipment, and a swinging lever operatively connected to the rod. of means for opcratively connecting said swinging lever with the dead lever, including a capstan, a flexible member winding on the capstan, the normal travel of the push rod operating the swinging lever independently of the capstan, means carried by the swinging lever and coacting with the capstan operating upon undue travel of the push rod and swinging lever for imparting rotation to the capstan, and means for bolding the 'apstan against retrograde rotation.

12. The combination with the push rod. a d ad lever of an air brake equipment, and a swinging lever operatively connected to the rod, of an operative connection between said swinging lever and the dead lever. including a capstan, a flexible member winding on the capstan, said swinging lever having swinging movement with respect to the axial center of the capstan. an operative connection between the push rod and said swinging 1ever. the normal travel of the push rod operating the swinging lever independently of.

the capstan, coacting means carried by the swinging lever and the capstan forimparting rotation to the capstan upon undue travel of the push rod. and means for holding the capstan against retrograde rotation.

3. The combination with'the push rod. a dead lever of an air brake equipment, and a swinging lever.operative]; connected to the rod. of means for operatively connecting said swinging lever with the dead lever. including a capstan. a flexible member winding on the capstan, means carried by the swinging lever and eoacting with the capstan operatin upon undue travel of the push rod for lmparting rotation to the capstan, said capstan being provided with a plurality of circumferentially arranged elongated ratchet teeth and having a short ratchet tooth between each pair of adjacent elongated ratchet teeth, and a pawl engageable with said teeth, said pawl normally c0- acting with an elongated tooth but engaging a short tooth upon undue outward movement of the push rod and engaging the next succeeding long tootlrupon the subsequent working movement of the push rod.

4. In combination with the push rod and a dead lever of an air brake equipment, a swinging lever. means for connecting the lever to the push rod whereby the lever is oscillated upon reciprocation of the push rod, and means for operatively connecting the swinging lever with the dead lever, including a capstan. a flexible member winding on the capstan, the normal movementof the push rod operating the swinging lever independently of the capstan, means operating upon undue travel of the push rod and swinging lever for imparting rotation to the capstan to wind the flexible member thereon. and means for holding the capstan against retrograde rotation.

5. A slack adjuster for a bake mechallislu comprising a capstan provided with a plurality of circlnnferentially arran ed elongated ratchet teeth and short ratc et teeth between each pair of adjacent elongated ratchet teeth, a flexible member comprised in the brake equipment and winding on the capstan. an operating member for the brake equipment. and a pawl engageable with the teeth of the capstan. said pawl normally enacting with an elongated tooth but engaging a short tooth upon abnormal functioning of the operating member for the equipment and engaging the next succeeding long tooth upon a subsequent working movement of said operating member.

In testimony whereof I hereunto afiix my signature.

JAMES W. CLARK. 

